Fliers frustrated with the discomforts of modern air travel might spare a thought this week for what flying was like a century ago when the first scheduled commercial airline in the world launched its inaugural flight from a Florida yacht basin.

On Jan. 1, 1914, a wood-and-muslin Benoist XIV flying boat, powered by a noisy, six-cylinder, 75-horsepower engine, took off from St. Petersburg, Fla., with its pilot and one passenger sitting on a small wooden bench, exposed to the elements. The rickety seaplane traveled 18 miles...